1. Field of the Invention
This invention relates to a weaving loom, more particular to a weaving loom, which is provided with a circulating magnetic shuttle that circulates along an endless loop.
2. Description of the Related Art
In a conventional weaving loom, a reciprocating shuttle reciprocates along a straight race rail. When in a picking motion, the flying speed of the reciprocating shuttle is accelerated from 0 to a high constant speed, and is then braked and decelerated to 0. Subsequently, the same picking motion is repeated in the opposite direction, thereby increasing largely the weft picking time.
To overcome the time-consuming problem, the applicant heretofore proposed an improved weaving loom, which is provided with a circulating magnetic shuttle. Referring to FIG. 1, the improved weaving loom 1 is shown to include a driving wheel 111 that drives a driving belt 113 to circulate. A series of magnets 114 is secured to the belt 113 for attracting and driving a magnetic shuttle 13 to circulate along an endless loop. The shuttle 13 picks a weft with the assistance of a weft swinging rod 16, and then moves the weft over a reed assembly 20, which is held on a swing arm 221 that is fixed on a rotating shaft 222. When the rotating shaft 222 rotates, the reed assembly 20 beats the weft 16. Two series of guiding rollers 12 are disposed respectively around a driving wheel 111 and a driven wheel 112 so that, when moving along two curved portions of a race rail 101, the shuttle 13 does not take off and deviate from the race rail 101 because of the centrifugal force that is generated. The conventional weaving loom 1 suffers from the following disadvantages:
1. The structure of the weaving loom 1 is relatively complicated. For example, a relatively long race rail 101 is needed to be disposed around the driving belt 113, thereby serving as a passage of the shuttle 13. In addition, a large number of guiding rollers 12 are disposed around the driving wheel 111 and the driven wheel 112 so as to guide the shuttle 13 to move along a curved path, thereby preventing the deviation of the shuttle 13 from an endless loop. As a result, it is difficult to manufacture the weaving loom 1, thereby increasing the manufacturing costs.
2. The shuttle 13 cannot move smoothly on the race rail 101. Ideally, the portion of the belt 113 between the driving wheel 111 and the driven wheel 112 should be in a horizontal position. However, during the movement of the magnets 114 between the driving wheel 111 and the driven wheel 112, the portion of the belt 113, to which the magnets 114 are attached, is slightly lower than the remaining portion of the belt 113, which is located between the driving wheel 111 and the driven wheel 112 due to the weight of the magnets 114. The larger the distance between the wheels 111, 112, the more serious the deviation of the magnets 114 from their predetermined circulating path. It is unavoidable, when weaving wider fabrics, to increase the distance between the wheels 111, 112. As a result, the belt 113 and magnets 114 cannot circulate smoothly at a high speed. Furthermore, because the shuttle 13 moves on the race rail 101, and contacts frequently the guiding rollers 12, it cannot fly smoothly along the endless loop, thereby reducing the weaving efficiency.
3. It is difficult to maintain and repair the weaving loom 1. To descend the gravity center of the weaving loom 1 and reduce the vibration of the same, the race rail 101 and the guiding rollers 12 are disposed on a lower portion of the weaving loom 1 along with the swinging arm 221 and the rotating shaft 222. Because they are disposed relatively close to each other, it is difficult to maintain and repair the weaving loom 1.